Fraudulent Inducement - or oversight?

Last week I signed an offer letter for a new job. There were no employment contingencies on the letter. I signed on a Wednesday, and told them I'd be resigning from my current position the follwing Monday.

After I resigned that morning, I notified the new employer. End of day Monday they send m3 a 2 year non-compete with strict language that they refused to alter, beyond reducing the term by a year. The language would clearly prohibit me from working in my field for a year.

Since they did this after resignation, they've put me in a horrible situation..,either needing to go back to current employer or sign their NS contract. Is there any legal recourse? Even if it's truly the "oversight" they say it is, it's a HUGE problem for me now.